Smart-multifunctional nano coatings

Smart multifunctional Nano coatings are designed to offer advanced multifunctional surface properties in combination with nanoparticles. In general, development of smart-multifunctional nanocoatings are involved with many more complex steps. We have demonstrated simple methods to fabricate multifunctional coatings on the various (Glass and Ti-alloy) substrates from a formulation via dip coating technique.

Case I: Anti-reflective and self-cleaning coating was developed using synthesized hierarchical mesoporous silica nano-particulates (MSNPs) and titania nanoparticles along with a siloxane resin and other additives. Dispersion of nanoparticles, compatibility of the dispersant along with solvents, resin and catalyst were examined. A systematic study was carried out to investigate the effect of additives on the microstructure, optical property and wettability of the coatings. Replacement of 0.5wt% mesoporous silica nanoparticles (200 nm) with 0.5wt% modified mesoporous titania nanoparticles (20-30nm) in the formulation enhanced the light transmission and provided high hydrophobicity due to in-situ formation of raspberry-like particles during film formation. The hierarchical arrangement of nanoparticles by the process of self-assembly along with the polymerization of resin developed hierarchical micro and nanoscale structure on the coated surface because of the in-situ generation of raspberry-like particles during film formation.  The optimum composition of the coating has anti-reflective property with maximum transmittance of 99.6% (364 nm) with an absolute increase in transmittance of 5.3% in the wavelength range of 360-800nm with a contact angle of 140^o with water. The addition of Hexamethyldisilazane (HMDS) into the formulation enhanced the hydrophobicity of the coatings by extending the formation of more micro-nano scale structure. Presence of unique pore structure of mesoporous nanoparticles and hierarchical arrangement of the particles on the coated matrix is responsible for less light scattering and thus achieve high transmission. The surface topography of the coatings reveals that the formation of more multilayer packing of the particles in an oriented manner helped in increase in surface roughness and thus leads to bring more hydrophobicity. The presence of a self-assembly strategy along with in-situ generated hierarchical raspberry-like particles during film formation has demonstrated a novel way of developing mechanically, thermally stable anti-reflective and self-cleaning coatings for the first time to the best of our knowledge. Moreover, the coated film exhibited a self-cleaning effect with/without the water and a photocatalytic effect with organic pollutants. Same time the developed coatings have 5B adhesion, significant humidity resistance, passed the 3H pencil hardness test and are thermally stable up to 250^oC. The developed process is also suitable for low temperature organic substrates, feasible for scale-up production and the stable formulation can be available in a two-pack system. The developed coating has the potential for large indoor and outdoor applications that require mechanically robust and durable self-cleaning functions including windowpane, optical and solar systems, etc. 

Case II: In another example, a heat resistant and low co-efficient of friction (COF) composite coatings on a medical device is developed using resin along with in-situ generated silica and titania nanoparticles. Similarly, in another study, alumina nanoparticles produced from ESP dust waste were used to produce transparent scratch-resistant coatings on glass substrate

Dr. Mamata is a Material scientist specializing in Smart multi-functional coatings, Colloidal processing of fine particles to produce nanostructured components, Nanocomposites and Pickering emulsion, She holds a Ph.D. degree in Materials science from Indian institute of Technology, Kharagpur. She has around twenty years of research experience in both Industry and academic domain. Dr. Mamata has worked as a scientist with Tata Research Development and Design Centre, a Division of TCS, Pune and as a Senior scientist with Dow Chemical, Pune for several years. Currently, she is working as a Senior manager at JSW Steel Coated Products Private Limited, Thane, India. She has 3 patents and 17 Publications in to her credit with h index 10.